Search Results (217)

Neuroimplants represent an emerging medical technology, offering new therapeutic approaches for severe neurological and psychiatric disorders. One of the key limitations to long-term neuroimplant performance is the foreign body response elicited by intracortical implantation. Among the contributing cell types, astrocytes play a central role in glial scar formation around the implant, which can compromise device functionality. Immunofluorescence of glial fibrillary acidic protein (GFAP) provides a well-established marker of astrogliosis (neuroinflammation), yet quantitative and reproducible assessment of astrocyte morphology remains challenging due to the complexity and variability of image analysis approaches. Here, we aimed to quantitatively assess implantation-induced astrogliosis and to determine how classifier training strategy influences segmentation outcomes and morphometric measurements. We present a machine learning-assisted pipeline based on the LabKit plugin in Fiji for segmentation and morphometric analysis of GFAP-positive astrocytes in peri-implant scar versus distant cortical regions. Using this approach, we demonstrate an increase in GFAP expression, cell area, and astrocytic process length as well as the redistribution of GFAP signal along astrocytic processes within scar regions. We show that different classifier training strategies produce systematically distinct segmentation outcomes, with rule-compliant annotation improving agreement with manually defined ground truth. These findings highlight the critical role of annotation strategy in shallow learning-based segmentation and provide a practical framework for improving reproducibility of astrocyte morphometry in studies of neuroinflammation and neuroimplant biocompatibility. Full article

The regulation of chloride levels is a crucial part of controlling inhibitory signals, but does not occur uniformly throughout the body. Recent data suggest that chloride is regulated within localized “microdomains” which are defined by the interaction of KCC2 and NKCC1, structural restraints on cells due to their internal structure, the metabolic condition of the cell, and the external environment modified by astrocytes. The gradients of chloride concentrations within these compartment-specific microdomains define the local chloride reversal potential, and thereby determine the directionality (i.e., whether excitatory or inhibitory), magnitude, and timing of GABAergic inhibition. The disruption of this organized chloride gradient within microdomains impairs the stability of inhibitory activity at multiple levels of integration, including dendritic input, spike timing, interneuron synchronization, and network oscillation. Disturbances in inhibitory stability have been found in a variety of diseases, including epilepsy, neonatal seizure, neuropathic pain, and schizophrenia-spectrum disorders. This supports the hypothesis that disturbances in chloride homeostasis lead to a loss of stability in cortical circuits. This review will provide a synthesis of the molecular, spatial, and circuit level principles involved in the regulation of chloride and discuss how failures of these mechanisms produce clinically relevant disturbances in inhibitory signal processing. In addition, we will be discussing new therapeutic strategies for the restoration of chloride homeostasis, including KCC2 repair, selective modulation of NKCC1, targeting astrocytes, and microenvironmental engineering. Overall, the studies reviewed here provide a unified model for understanding the pathophysiology of inhibitory dysfunction, and demonstrate that the regulation of chloride microdomains provides a novel and promising area of research for translational intervention. Full article

The 3-nitropropionic acid (NPA) promotes neurological alterations in the striatum, hippocampus and vicinal motor and pre-motor cortical areas, and in the cerebellum. The neurological alterations induced by systemic NPA administration resemble those found in Huntington’s disease. In previous works, we have shown that intraperitoneal (i.p.) administration of kaempferol can efficiently protect against striatum degeneration and against motor neurological dysfunctions induced by NPA. In this work, we show that i.p. administration of kaempferol also protects against the increase in pro-inflammatory cytokines that potentiate the activation of complement C3 protein (a biomarker of A1-type reactive astrocytes generation) and overproduction of neurotoxic amyloid β (Aβ) peptides in the cerebellum of rats treated with acute i.p. administration of NPA. In NPA-treated rats, large multipolar neurons of cerebellar nuclei and Purkinje neurons of the cerebellar cortex are the cells that are most intensely stained by anti-C3 and by anti-Aβ antibodies. In addition, we found that kaempferol also protects against the NPA-induced increase in phospho-tau 217 and phospho-tau 181 in the cerebellum, and our results pointed out that the NPA-induced phospho-tau 217 colocalizes with Aβ(1-42) more closely than phospho-tau 181, both in dentate nucleus and cerebellar cortex. Also, our results unveil another novel brain-protective action of i.p. kaempferol co-administration: namely, its ability to prevent microhemorrhages induced in the cerebellar nuclei area by acute NPA administration. In conclusion, the results of this work show a potent protection of kaempferol against the NPA-induced increase in degeneration biomarkers in the cerebellum. Full article

Background: Danhong injection (DHI), a standardized traditional Chinese medicine formulation, has shown clinical benefits in treating cerebrovascular diseases. Blood–brain barrier (BBB) disruption is a key pathological feature of ischemic stroke, but its modulation by DHI under hyperlipidemic conditions remains unclear. This study aimed to investigate the protective effects and mechanisms of DHI in cerebral ischemia/reperfusion injury (CI/RI) under hyperlipidemia, focusing on BBB integrity and the Wnt/β-catenin signaling pathway. Methods: Rats were divided into control, ischemic, hyperlipidemic, and treatment subgroups to evaluate DHI’s dose-dependent effects and pathway specificity using DKK1 inhibition. Assessments included neurological scores, TTC and Nissl staining, TEM, and molecular analyses (qRT-PCR/Western blot/immunofluorescence/immunohistochemistry). Results: DHI significantly improved neurological function, reduced cerebral infarct size, and alleviated cortical damage. DHI treatment upregulated the expression of tight junction proteins (Claudin-5, Occludin, ZO-1) and downregulated MMP-9 expression. Mechanistically, DHI promoted the nuclear translocation of β-catenin and increased the expression of Wnt3α, p-GSK-3β, and Cyclin D1, thereby activating the Wnt/β-catenin pathway. Additionally, DHI treatment increased the count of NeuN-positive neurons, suppressed astrocyte activation, and markedly reduced IgG infiltration in the ischemic cerebral cortex. These effects were reversed by DKK1. Conclusions: The results indicate that DHI protects BBB integrity and alleviates CI/RI in hyperlipidemic rats independently of direct lipid-lowering activity. Specifically, DHI activates the Wnt/β-catenin pathway by enhancing β-catenin nuclear translocation, which in turn mediates the upregulation of tight junction proteins and suppression of MMP-9, ultimately preserving BBB integrity. These findings support its therapeutic potential in ischemic stroke with comorbid hyperlipidemia. Full article

Astrocytes critically regulate states of consciousness, yet their molecular profiles across wake, sleep, and general anesthesia remain unclear. This study conducted proteomic and phosphoproteomic analyses of rat cortical astrocytes across these states using sevoflurane. Data quality was validated using principal component analysis (PCA) and Pearson correlation coefficient (PCC). Proteomics showed state-specific signatures: sleep and anesthesia shared similar changes (downregulated structural proteins, upregulated membrane transport complexes) but diverged in molecular expression. Anesthesia specifically suggested potential activation of cellular differentiation/structural plasticity-related pathways but implied potential disruption of metabolism and molecular clearance processes compared to sleep. Phosphoproteomics revealed the unique phosphorylation changes during general anesthesia compared to wake and normal sleep: downregulated phosphorylation of nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) at Ser188, suggesting the potential suppression of nuclear transcription and/or cell cycle activity, which may act as a potential molecular signature associated with the anesthetic state. Clustering analysis showed that sleep was associated with upregulated mRNA processing, while anesthesia indicated potential enhancement of synaptic signaling and suggested possible suppression of development-related programs. In summary, astrocytes undergo extensive molecular reprogramming during transitions of consciousness; while they share common features in morphological remodeling, sleep and anesthesia differ fundamentally in astrocytic molecular outcomes, offering new insights into astrocytic roles in unconsciousness. Full article

Accurate identification of Alzheimer’s disease (AD)-related cellular characteristics from microscopy images is essential for understanding neurodegenerative mechanisms at the cellular level. While most computational approaches focus on macroscopic neuroimaging modalities, cell type classification from microscopy remains relatively underexplored. In this study, we propose a hybrid vision transformer–convolutional neural network (ViT–CNN) framework that integrates DeiT-Small and EfficientNet-B7 to classify three AD-related cell types—astrocytes, cortical neurons, and SH-SY5Y neuroblastoma cells—from phase-contrast microscopy images. We perform a comparative evaluation against conventional CNN architectures (DenseNet, ResNet, InceptionNet, and MobileNet) and prompt-based multimodal vision–language models (GPT-5, GPT-4o, and Gemini 2.5-Flash) using zero-shot, few-shot, and chain-of-thought prompting. Experiments conducted with stratified fivefold cross-validation show that the proposed hybrid model achieves a test accuracy of 61.03% and a macro F1 score of 61.85, outperforming standalone CNN baselines and prompt-only LLM approaches under data-limited conditions. These results suggest that combining convolutional inductive biases with transformer-based global context modeling can improve generalization for cellular microscopy classification. While constrained by dataset size and scope, this work serves as a proof of concept and highlights promising directions for future research in domain-specific pretraining, multimodal data integration, and explainable AI for AD-related cellular analysis. Full article

Aging disrupts the neurovascular unit (NVU) and blood–brain barrier (BBB), elevates glial inflammatory tone, and compromises hippocampal memory. Environmental enrichment (EE)—a multimodal, lifestyle-based intervention—improves cognition, but its association with BBB/NVU and FNDC5/irisin-related signaling in aging remains incompletely understood. Aged male C57BL/6J mice (21 months old) were housed under EE or standard conditions for 11 weeks. Hippocampal-dependent spatial working memory was assessed using the radial eight-arm maze, and neuronal (NeuN), glial (Iba1, GFAP), and BBB/NVU markers (AQP4 endfoot polarity, occludin, ZO-1, PECAM-1, microvessel length/density) were quantified. FNDC5/irisin-related signaling was evaluated by measuring PGC-1α, FNDC5/irisin, IGF-1, BDNF, pAKT, and serum irisin. EE improved spatial working memory in aged mice, reducing working-memory errors, increasing correct choices before the first error, and enhancing path efficiency. EE attenuated the age-related decline of NeuN(+) neurons in the hippocampal CA1 and CA3 regions and suppressed microglial and astrocytic activation. EE strengthened BBB/NVU integrity by restoring AQP4 endfoot polarity, increasing occludin, ZO-1, and PECAM-1, and increasing cortical microvessel length and density. At the molecular level, EE upregulated the PGC-1α–FNDC5/irisin–IGF-1 axis and was accompanied by increased cortical BDNF and pAKT levels, as well as elevated circulating irisin, changes that occurred in parallel with NVU stabilization and reduced glial activation. EE mitigates age-related cognitive decline in association with coordinated neuronal, glial, vascular, and FNDC5/irisin-related signaling changes, supporting BBB/NVU preservation and cognitive resilience during aging. Full article

Traumatic brain injury (TBI) often leads to long-lasting motor deficits, but the underlying cellular mechanisms still remain poorly understood. In this study, we examined glial and neuronal responses after focal cortical aspiration injury of the right hindlimb sensorimotor cortex in adult male rats. This is a model we have previously shown induces persistent gait asymmetry and postural deficits. Immunohistochemical analysis of activated microglia/macrophages (CD11b, IBA-1), astrocytes (GFAP), and neurons (NeuN) was performed bilaterally in the peri-lesional cortex at 3, 7, 14, 21, and 28 days post-injury (n = 3–6 per time point). The injury induced an early, sharply localized increase in CD11b-positive myeloid cells in the injured hemisphere, suggesting an activation of both resident microglia and infiltrating monocyte-derived cell. This was followed by a more sustained IBA-1-positive microglial activation that gradually extended contralaterally. Astrocytic activation showed a delayed but prolonged profile, rising ipsilaterally within the first week, peaking around two weeks, and becoming bilaterally elevated by four weeks. Sham-operated animals showed only basal glial immunoreactivity without signs of hypertrophy or reactive morphology at any time point. NeuN immunoreactivity remained stable across timepoints, suggesting preservation of neuronal soma labeling without evidence of overt secondary neuronal loss. These findings reveal a staged and spatially distinct glial response to focal cortical injury, with early myeloid activation, prolonged microglial reactivity, and delayed bilateral astrogliosis. Together, these findings are consistent with the possibility that persistent motor deficits after focal TBI arise from both primary tissue loss within the lesion core and peri-lesional glial remodeling, highlighting glial–neuronal interactions as a potential therapeutic target. Full article

Background/Objectives: Astrocytes are key regulators of brain energy homeostasis, integrating glucose metabolism with antioxidant support for neuronal function. Dysregulation of these processes contributes to neurodegenerative diseases, including Alzheimer’s disease. Andrographolide, a bioactive diterpenoid from Andrographis paniculata, has been reported to exert neuroprotective effects through the modulation of Wnt/β–catenin signaling and neuronal metabolism; however, its actions on astrocytic metabolic pathways remain insufficiently characterized. Methods: Here, we investigated the effects of andrographolide on metabolic and redox parameters in primary mouse cortical astrocytes. Results: Andrographolide increased glucose uptake and antioxidant capacity without affecting AMPK activation or the activity of core glycolytic enzymes. Instead, it selectively enhanced glucose-6-phosphate dehydrogenase activity, promoting glucose flux through the pentose phosphate pathway in a partially Wnt-dependent manner. This metabolic reprogramming was associated with increased NADPH availability and glutathione levels, together with a reduced ATP/ADP ratio, consistent with a shift toward redox maintenance rather than maximal energy production. Conclusions: Collectively, these findings highlight astrocytic metabolic plasticity as a relevant and underexplored target of andrographolide and support the concept that natural compounds can enhance brain resilience by modulating glial redox metabolism. Full article

Background: The insulin-like growth factor 2 receptor (IGF-2R), also known as the cation-independent mannose 6-phosphate receptor (CI-M6PR), is emerging as a critical receptor for brain function and disease. IGF-2R, in fact, plays a key role in long-term memory, and its activation by several ligands shows beneficial effects in multiple neurodevelopmental and neurodegenerative disease models. Thus, its targeting is very promising for neuropsychiatric therapeutic interventions. IGF-2R’s main known functions are transport of lysosomal enzymes and regulation of developmental tissue growth, but in the brain, it also controls learning-dependent protein synthesis underlying long-term memory. However, little is known about this receptor in brain cells, including its cell-type-specific and subcellular expression. Methods: We conducted a comprehensive investigation to comparatively assess IGF-2R protein levels in different brain cell types across various brain regions in adult male C57BL/6J mice using dual and multiplex immunofluorescent staining with cell-type-specific markers. The IGF-2R protein distribution was also compared with Igf2r mRNA expression in publicly available single-cell RNA sequencing databases. Results: A ranking of IGF-2R levels in the soma of various cell types in the hippocampus and cortical regions revealed that the highest enrichment is, by far, in excitatory and inhibitory neurons, followed by vascular mural cells and subpopulations of oligodendrocyte lineage cells, with low to undetectable levels in astrocytes, microglia, vascular endothelial cells, and perivascular fibroblasts. High levels of IGF-2R were also found in ependymal cells, choroid plexus epithelial cells, and a subpopulation of meningeal fibroblast-like cells. IGF-2R was found in dendritic and putative axonal compartments throughout the brain, with particularly high levels in the stratum lucidum. The receptor’s protein distribution aligned with that of the mRNA in mouse brain databases. Conclusions: These results suggest that IGF-2R-mediated functions in the brain vary across different cell types and subcellular compartments, with the most active roles in specific subpopulations of neurons, mural cells, ependymal cells, meningeal cells, and cells of the oligodendrocyte lineage. This study advances our understanding of IGF-2R’s distribution in the brain, which is essential for formulating new hypotheses about its functions and therapeutic targeting. Full article

Thought processes in the brain occur as it continually modifies its use of energy. This review integrates research findings from molecular neurology, vascular physiology and non-equilibrium thermodynamics to create a comprehensive perspective on thinking as a coordinated energy process. Data shows that there is a relationship between the processing of information and metabolism throughout all scales, from the mitochondria’s electron transport chain to the rhythmic changes in the microvasculature. Through the cellular level of organization, mitochondrial networks, calcium (Ca²⁺) signals from astrocytes and the adaptive control of capillaries work together to maintain a state of balance between order and dissipation that maintains function while also maintaining the ability to be flexible. The longer-term regulatory mechanisms including redox plasticity, epigenetic programs and organelle remodeling may convert short-lived states of metabolism into long-lasting physiological “memory”. As well, data indicates that the cortical networks of the brain appear to be operating close to their critical regimes, which will allow them to respond to stimuli but prevent the brain from reaching an unstable energetic state. It is suggested that cognition occurs as the result of the brain’s ability to coordinate energy supply with neural activity over both time and space. Providing a perspective of the functional aspects of neurons as a continuous thermodynamic process creates a framework for making predictive statements that will guide future studies to measure coherence as a key link between energy flow, perception, memory and cognition. Full article

Traumatic brain injury (TBI) causes cortical dysfunction by increasing oxidative stress, neuroinflammation, apoptosis, and mitochondrial dysregulation, and impairing neurotrophic signaling and neurogenesis. This systematic review aimed to evaluate the effectiveness of exercise training on cortical molecular dysregulation and motor function in post-TBI. Following PRISMA 2020 guidelines, PubMed, EMBASE, and Web of Science were searched up to August 2025. Of 1173 records, 35 studies involving exercise training in post-TBI animal models were included. Exercise training protocols included voluntary wheel running, treadmill running, and swimming, with durations ranging from 7 to 63 days. Study quality was assessed using the CAMARADES checklist. Exercise training increased cortical glutathione and Na⁺/K⁺-ATPase activity and reduced oxidative stress in post-TBI. It reduced microglial, astrocytic reactivity, and pro-inflammatory markers, including IL-1β and TNF-α expression in post-TBI. It also reduced caspase activity while increasing heat shock protein 20 (HSP20), thereby downregulating cortical apoptosis in post-TBI. It enhanced motor function, cortical neurogenesis, and neurotrophic factors signaling, including BDNF, in post-TBI. Exercise training improved motor function and cortical neuroprotection by reducing oxidative stress, neuroinflammation, and apoptosis, while enhancing neurotrophic signaling and neurogenesis in post-TBI rodents, but the regulation of let-7c, IL-6, and mitochondrial function remained unclear. (PROSPERO: CRD420251073725) Full article

Alzheimer’s disease (AD) is increasingly recognized as a disorder of cerebral energy metabolism, where impaired glucose utilization contributes to disease pathology. Medium-chain fatty acids (MCFAs), such as decanoic acid (C10), have emerged as promising metabolic substrates due to their ability to bypass glycolytic deficits and support mitochondrial function. In this study, we investigated the metabolic impact of C10 in the 5xFAD mouse model of AD and in human induced pluripotent stem cell (hiPSC)-derived astrocytes carrying familial AD mutations. Utilizing stable ¹³C-labeled metabolic tracers, we demonstrated that while [U-¹³C]glucose metabolism was largely preserved in cortical slices of 6-month-old 5xFAD female mice, [1,2-¹³C]acetate uptake was significantly reduced, suggesting impaired astrocytic metabolism. [U-¹³C]C10 was efficiently metabolized in both WT and 5xFAD brain slices, particularly in astrocytes, as indicated by high labeling of glutamine and citrate. Furthermore, C10 competitively inhibited glucose and acetate metabolism, suggesting its potential as an auxiliary energy substrate. In hiPSC-derived astrocytes, AD-specific metabolic responses to C10 varied by mutation, with only partial alterations in oxidative glucose metabolism observed in APP and PSEN1 variants, highlighting genotype-dependent metabolic alterations. While AD-related mutations in the hiPSC models did not lead to robust deficits, the in vivo environment in the 5xFAD model is associated with measurable metabolic changes in astrocytes. These findings underscore astrocytic metabolic dysfunction in AD and suggest that C10 supplementation may restore brain energy by supporting astrocytic oxidative metabolism. Full article

Severe traumatic brain injury includes neurovascular unit (NVU) damage that is linked to the later development of neurodegenerative diseases. Cell-type-specific contributions and crosstalk between cells of the neurovascular unit following brain injury remain poorly defined in human cells. Here, we developed a three-dimensional (3D) human NVU model using silk–collagen scaffolds to examine cellular responses to controlled cortical impact (CCI). Using this platform, we show that CCI induced acute cell death in astrocytes, microglia, and endothelial cells but spared pericytes, which occurred independently of classical apoptotic or necroptotic pathways. Astrocytes and microglia were the primary sources of early bioactive IL-1β release, while endothelial junctional integrity was differentially regulated by support cells: astrocytes destabilized VE-cadherin, pericytes preserved barrier proteins, and microglia contributed to Claudin-5 loss in multicellular settings. Conditioned media experiments demonstrated that soluble factors from injured support cells alone were sufficient to disrupt endothelial junctional proteins (ZO-1 and Occludin) and induce inflammatory adhesion molecules (ICAM-1 and VCAM-1). Together, these findings define cell-type-specific injury responses and reveal how NVU interactions regulate vascular dysfunction after trauma, providing a human-based framework for understanding blood–brain barrier (BBB) disruption following traumatic brain injury (TBI). Full article

Background/Objectives: The cerebral cortex is critical for neurological functions that are strongly affected by the aging process. Astrocytes play a central role in maintaining neurotransmitter balance and regulating antioxidant and anti-inflammatory responses, but these physiological functions may also decline with age. This study aimed to investigate the effects of melatonin, a molecule with known antioxidant, anti-inflammatory and neuroprotective properties, on astrocytes of mature cortical tissue obtained from adult Wistar rats. Methods: Primary cortical astrocyte cultures were obtained from neonatal and 90-day-old Wistar rats and treated with melatonin (300 µM for 24 h). We assessed cell viability and metabolism (MTT and extracellular lactate levels), glutamine synthetase (GS) activity, glutathione (GSH) content, release of cytokines, and the expression of genes and proteins associated with oxidative stress and inflammation by RT-qPCR and Western blotting. Results: Melatonin did not affect cell viability or lactate production. Moreover, there were no changes in GS activity, a key enzyme in glutamate metabolism, or in GSH levels, an antioxidant defense molecule synthesized by astrocytes. However, melatonin significantly reduced the expression of the nuclear factor NFκB, cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS), while increasing interleukin 6 and 10 levels. Melatonin also upregulated the gene expression of the transcriptional factors Nrf2 and sirtuin 1 (SIRT1) and downregulated AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), while PGC-1α protein levels remained unchanged. A complementary analysis of astrocytes obtained from neonatal rats showed that melatonin did not change metabolic or redox parameters under basal conditions. Conclusions: Melatonin exerted anti-inflammatory effects on adult astrocyte cultures, likely through modulation of protective signaling pathways, such as Nrf2/SIRT1. These findings highlight the potential role of melatonin in preserving astrocytic function and mitigating age-related neuroinflammatory processes. Full article